National security agent Lu Ci died in an anti-terrorism mission, but when he woke up, he found that he was Lu Cheng, a young Chinese in London in 1881 - the son of a frail translator at the Qing Dynasty embassy in Britain who had just lost his father.
Outside the window is the foggy Victorian city, and across the street lives Sherlock Holmes.
Lu Ci, who carries all the professional memories of national security training in the 21st century, has to start over in this frail body. After he used his knowledge of modern forensic science to solve his first murder on the East End docks, Holmes knocked on his door. From testing each other to fighting side by side, two detectives with completely different thinking patterns formed a strange tacit understanding in London under the gaslight.
But in this crime-ridden era, a mathematics professor named Moriarty is weaving a web of evil that envelopes London. Lu Cheng used modern network analysis thinking to deconstruct this "criminal empire", but found that he had also become prey in the eyes of spiders.
From the East End slums to the upper class salons, from the secret archives of the British Museum to the life and death showdown at the Reichenbach Falls - this is a story about identity and belonging, justice and choice.
The lights at 221C Baker Street will always be on for those returning home at night.
